Apparatus for weight heads assembly used on dumbbells

ABSTRACT

Weight head assembly for dumbbells that eliminates a weak point on the handle bar, so as to increase the durability of a handle bar on dumbbells. Under present invention, the ‘stub’ portion, where the handlebar is inserted into the weight heads on the two ends of the bar, need not be machined own in size, and can thus withstand more wear and tear for regular usage in fitness training. The cost of manufacturing the handle bar, and as a result of the increase durability, will help the fitness industry greatly when making new dumbbells.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates generally to design and construction of dumbbell weight heads assembly used on fitness training equipment.

Traditional dumbbells have a handle bar with two ends attaching to the bells, or called weight heads.

To prevent the two dumbbells from sliding towards the center of the handle bar, two collars are commonly used for this purpose. The load-bearing portion (called ‘stub’) on the two ends of the handle bar is usually machined down to reduce the diameter so that the collars would properly be ‘pinched’ in place and serve to prevent the dumbbells from sliding towards the center of the handle bar. See FIG. 1, showing prior art industry usage.

The problems with the common industry usage include, at least, first, tremendous pressure is exerted to the junction point between the stub portion (which has reduced diameter, thus reduced strength) and the central handle bar, and second, the high cost for the need to machined down the diameter of the stub to provide the hold pattern for the collars as well as the load-bearing portion that takes the weight head.

OBJECTS AND SUMMARY OF THE INVENTION

Present invention provides an improved dumbbell assembly without causing a weakened portion of the handle bar, thus making the dumbbell more durable, and an inexpensive mechanism for securing the dumbbells in place.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the preferred embodiments of the invention and together with the description, serve to explain the principles of the invention.

A brief description of the drawings is as follows:

FIG. 1 shows common dumbbell assembly, having reduced (weakened) stub.

FIG. 2 shows a first embodiment of the central handle bar of present invention.

FIG. 3 shows a first embodiment of weight heads of present invention.

FIG. 4 shows an exploded view for the first embodiment of present invention.

FIG. 5 shows a partial cut-out view of the first embodiment of present invention.

FIG. 6 shows a second embodiment of the central handle bar of present invention.

FIG. 7 shows a second embodiment of weight heads of present invention.

FIG. 8 shows an exploded view for the second embodiment of present invention.

FIG. 9 shows a partial cut-out view of the second embodiment of present invention.

FIGS. 10 and 11 show a third embodiment of present invention.

FIGS. 12 and 13 show a fourth embodiment of present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1, a common dumbbell is shown. Two collars are used to stop the weight heads from sliding towards the middle of the handle bar. The collars have an opening sized to fit the stub portion of the handle bar. The stub portion is machined from an integral handle bar and becomes smaller in diameter, and serves as the load-bearing part inserted into the weight heads.

A lock nut is used to secure the weight head.

FIGS. 2-5 show the first embodiment of present invention.

FIG. 2 shows a central handle bar having 2 non-through holes drilled in axially from the end. Thread lines are machined to the inside wall of said non-through holes. The handle bar's outside diameter remains the same throughout.

FIG. 3 and 4 show the cut-out view of the weight head, which has a through hole divided into 3 sections, having 3 respective diameter. The ‘stub’ portion of the weight head receives the ‘stub’ portion of the handle bar. A second section of the weight head's through hole is sized to receive a bolt with an attached locking nut. Finally, a third section of the through hole is sized to receive the capping piece of a tool, such as a wrench, when tightening or loosening the bolt to secure the weight head to the handle bar.

FIG. 5 shows a cut-out view of assembled weight head to the handle bar, as depicted by present invention.

FIGS. 6-9 show a second embodiment of present invention.

In second embodiment, the bolt and the locking nut are separated. The end portion of the handle bar contains threads to receive locking nut. Like the first embodiment, the ‘stub’ portion on the handle bar remain the same diameter as the central portion of the handle bar, so that there will not be weak point in the load-bearing part of the handle bar.

The two end portions of the central handle bar will have machined threads to receive the locking nuts. To use the same weight head through hole configuration as in first embodiment, the threaded portion at two ends of the central handle bar will be machined down in diameter, as shown in FIGS. 6 and 8.

Alternatively, if the threaded portion on end portion of the handlebar is not machined down in diameter, as shown in FIGS. 10 and 11, then the weight head through hole configuration will consist of only 2 sections, one sized and threaded for receiving the ‘stub’ portion of the handle which contains screw threads, and another sized for receiving the capping piece of a tool, such as a wrench, when tightening or loosening the nut for the threaded portion of the stub.

As shown in FIGS. 10 and 11, central handle bar does not need the use of a pair of ‘collar’, simply because the weight heads will not slide inwards when the end of the thread on the central bar is reached.

FIGS. 12 and 13 show a fourth embodiment of present invention, wherein several of the individual features in the prior 3 embodiments are combined.

In this embodiment, the weight head contains 3 sections, similar to the 3 sections of the weight head in the first embodiment. However, the section for receiving the ‘stub’ portion of the handle bar is threaded.

The two ‘stub’ portions of the central bar is threaded for fittingly insertion into the weight head. Tow end portions of the central bar is machined down to reduce the size of the diameter, so as to fit in the second section of the weight head's through hole.

Two non-through holes, having machined threads in the inside wall, are made axially from two ends of the handle bar, so that a bolt with locking nut can be utilized to secure and tighten the weight head to the central bar, from both directions.

In summary, all the four embodiments in present invention greatly increase the durability of a central bar on dumbbells by eliminating the formation of a weak joint. 

1. Weight heads assembly apparatus, comprising: a. A central handlebar having threadlines machined into its inside circumferential wall from the two coaxial ends; b. A pair of bolts with locking nuts attached having external threadlines along the length of the bolts matching the internal threadlines of said central handlebar; and, c. Weight heads with through hole having three diameters machined to fittingly receive the outside diameter of said central handlebar, the outside diameter of said bolts, and diameter of capping tool for turning said locking nuts.
 2. Weight heads assembly apparatus, comprising: a. A central handlebar having some lengths of threadlines machined on the outside circumferential wall on two ends of said handlebar; b. A pair of locking nuts having inside threadlines matching those of the threadlines of said handlebar; c. Weight heads with through hole having 2 diameters machined to fittingly receive the outside diameter of said central handlebar, and diameter of capping tool for tightening said locking nuts.
 3. Weight heads assembly apparatus of claim 2, comprising: a. A central handlebar having its threadlines on two ends machined down to reduce the diameter; b. A pair of locking nuts having inside threadlines matching those of the threaded portion of said handlebar; c. Weight heads with through hole having three diameters machined, to fittingly receive the outside diameter of said central handlebar, the outside diameter of the threaded portion of said central handlebar, and diameter of capping tool for tightening said locking nuts.
 4. Weight heads assembly apparatus, comprising: a. A central handlebar having some lengths from both ends machined down to reduce diameter and further having non-through hole drilled in axially with threadlines on the inside wall of said non-through hole; b. Some lengths of said handlebar machined to produce threadlines, further inward from said reduced diameter of said handlebar; c. A pair of bolts with locking nuts attached having external threadlines along the length of the bolts matching the internal threadlines of said central handlebar; and, d. Weight heads with through hole having three diameters machined to fittingly receive the outside diameter of said central handlebar and further having threadlines, the outside diameter of the reduced diameter portion of said handlebar, and diameter of capping tool for tightening said locking nuts. 